const people = [
    {
        name: '张三',
        age: 18,
        role: 'admin'
    },
    {
        name: '李四',
        age: 19,
        role: 'user'
    },
    {
        name: '王五',
        age: 20,
        role: 'user'
    }
]

const allAdults = people.every(person => person.age >= 18)
const hasAdmin = people.some(person => person.role === 'admin')